Solid-state transducer assemblies with remote converter material for improved light extraction efficiency and associated systems and methods

ABSTRACT

Solid state transducer (“SST”) assemblies with remote converter material and improved light extraction efficiency and associated systems and methods are disclosed herein. In one embodiment, an SST assembly has a front side from which emissions exit the SST assembly and a back side opposite the front side. The SST assembly can include a support substrate having a forward-facing surface directed generally toward the front side of the SST assembly and an SST structure carried by the support substrate. The SST structure can be configured to generate SST emissions. The SST assembly can further include a converter material spaced apart from the SST structure. The forward-facing surface and the converter material can be configured such that at least a portion of the SST emissions that exit the SST assembly at the front side do not pass completely through the converter material.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. Pat. Application No.16/420,463, filed May 23, 2019, which is a divisional of U.S. Pat.Application No. 13/464,687, filed May 4, 2012, now U.S. Pat. No.10,347,609, which are incorporated herein by reference in theirentirety.

TECHNICAL FIELD

The disclosed embodiments relate to solid-state transducer (“SST”)devices and methods of manufacturing SST devices. In particular, thepresent technology relates to SST assemblies with remote convertermaterial for improved light extraction efficiency and associated systemsand methods.

BACKGROUND

Mobile phones, personal digital assistants (″PDAs″), digital cameras,MP3 players, and other portable electronic devices utilizelight-emitting diodes (″LEDs″), organic light-emitting diodes (″OLEDs″),polymer light-emitting diodes (″PLEDs″), and other SST devices forbacklighting. SST devices are also used for signage, indoor lighting,outdoor lighting, and other types of general illumination. FIG. 1A, forexample, is a partially schematic cross-sectional view of a conventionalSST device 10 a. The SST device 10 a includes a carrier substrate 20supporting an LED structure 12 that has an active region 14 (e.g.,containing gallium nitride/indium gallium nitride (GaN/InGaN) multiplequantum wells (″MQWs″)) between N-type gallium nitride (″N-GaN″) 16 andP-type gallium nitride (″P-GaN″) 18. A first contact 22 is on the P-typeGaN 18 and a second contact 24 is on the N-GaN 16 such that the firstand second contacts 22 and 24 are configured in a vertical arrangementon opposite sides of the LED structure 12. In other embodiments, theN-GaN 16 and the active region 14 may be recessed to expose the P-GaN18, and the first and second contacts 22 and 24 can be spaced laterallyapart from one another on forward-facing surfaces or backward-facingsurfaces of the N-GaN 16 and the P-GaN. In further embodiments, the SSTdevice 10 a can include backside contacts, wherein the second contact 24extends from the back side of the LED structure 12 into the N-GaN 16 andis electrically isolated from the first contact 22, the P-GaN 18, andthe active region 14. Electrical power can be provided to the SST device10 a via the contacts 22, 24, causing the active region 14 to emitlight.

The SST device 10 a can be configured as a “white light” LED, whichrequires a mixture of wavelengths to be perceived as white by humaneyes. LED structures typically only emit light at one particularwavelength (e.g., blue light), and are therefore modified to generatewhite light. One conventional technique for modulating the light fromLED structures includes depositing a converter material (e.g., phosphor)on the LED structure. For example, as shown in FIG. 1A, a convertermaterial 26 can be positioned over the front surface of the LEDstructure 12. In other conventional SST devices, such as the SST device10 b shown in FIG. 1B, the LED structure 12 can be positioned in arecessed portion 30 of the underlying carrier substrate 20, and theconverter material 26 can encapsulate the LED structure 12 to fill therecessed portion 30.

In operation, the LED structures 12 of the SST devices 10 a-b emit lighthaving a certain wavelength (e.g., blue light), and the phosphor of theoverlying converter material 26 absorbs some of the emitted photons.This absorption promotes the electrons of the converter material 26 tohigh unstable energy levels, which causes the converter material 26 toemit longer-wavelength photons (e.g., yellow light) when the electronsultimately relax to their original state. The combination of theemissions from the LED structure 12 and the converter material 26 isdesigned to appear white to human eyes when the wavelengths of theemissions are matched appropriately. The generated light can bemodulated by optional optical features (e.g., encapsulants or lenses 28)positioned over the converter material 26.

In both the LED devices 10 a-b shown in FIGS. 1A and 1B, the convertermaterial 26 is directly on the face of the LED structure 12, andtherefore the LED emissions (e.g., blue light) must travel completelythrough the converter material 26 before exiting the SST device 10 a-b.This trajectory through the converter material 26 decays the LEDemissions, and thereby reduces the light extraction efficiency of theSST devices 10 a-b. In addition, the converter material 26 spontaneouslyemits photons in random directions such that at least a portion of theconverter emissions (e.g., about half of the converter emissions) travelinwardly toward the LED structure 12. The inward converter emissionsthen reflect off of the face of the LED structure 12 at least oncebefore being extracted from the SST devices 10 a-b as useful light. Eachsuch reflection dissipates the emissions, and therefore multiplereflections decrease the light-extraction efficiency of the SST devices10 a-b.

To reduce the effects of the scattered light, the forward-facing surfaceof the LED structure 12 can be configured to have reflective properties.However, other considerations, such as current spreading,light-extraction efficiency, and electrical characteristics, may lead tosub-optimal reflectivity of the LED structure 12. To reduce reflectionsoff of the face of the LED structure 12, the converter material 26 ofthe SST device 10 b shown in FIG. 1B is configured to disperse theemissions laterally outward from the forward-facing surface of thecarrier substrate 20. The surfaces of the carrier substrate 20underlying the converter material 26 can be configured to have enhancedreflective properties without being bound by the operating constraintsof the LED structure 12.

LED devices have also been designed to include a converter materialspaced apart from an LED structure, such as the SST device 10 c shown inFIG. 1C. The emissions reflected backward from the remote convertermaterial 26 are less likely to hit the face of LED structure 12, andinstead reflect off of other surfaces that have enhanced reflectiveproperties. For example, the arrows shown in FIG. 1C illustrate that theemissions can reflect off of the forward-facing surface of the carriersubstrate 20 and/or a larger underlying support substrate 21. However,even when the forward-facing surfaces of the substrates 20, 21 includehighly reflective materials, the scattering properties of the convertermaterial 26 still result in multiple emission-dissipating reflectionsbefore the light exits the SST device 10 c. Moreover, the emissions muststill pass completely through the remote converter material 26 beforeexiting the SST device 10 c, which further reduces the light extractionefficiency of the SST device 10 c.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a partially schematic cross-sectional diagram of an SSTdevice configured in accordance with the prior art.

FIG. 1B is a partially schematic cross-sectional diagram of an SSTdevice configured in accordance with another embodiment of the priorart.

FIG. 1C is a partially schematic cross-sectional diagram of an SSTdevice configured in accordance with yet another embodiment of the priorart.

FIG. 2 is a partially schematic cross-sectional view of an SST assemblyconfigured in accordance with embodiments of the present technology.

FIG. 3 is a partially schematic cross-sectional view of an SST assemblyconfigured in accordance with other embodiments of the presenttechnology.

FIG. 4 is a partially schematic cross-sectional view of an SST assemblyconfigured in accordance with further embodiments of the presenttechnology.

FIG. 5 is a schematic view of a system that incorporates an SST assemblyin accordance with embodiments of the present technology.

DETAILED DESCRIPTION

Specific details of several embodiments of SST devices and assemblieswith remote converter material for improved light extraction efficiencyand associated systems and methods are described below. The term “SSTdevice” generally refers to solid-state devices that include asemiconductor material as the active medium to convert electrical energyinto electromagnetic radiation in the visible, ultraviolet, infrared,and/or other spectra. For example, SST devices include solid-state lightemitters (e.g., LEDs, laser diodes, etc.) and/or other sources ofemission other than electrical filaments, plasmas, or gases. SST devicescan also include solid-state devices that convert electromagneticradiation into electricity. The term “light extraction efficiency”generally refers to a ratio of the amount of light extracted from an SSTdevice to the total light generated in the SST device. A person skilledin the relevant art will also understand that the technology may haveadditional embodiments, and that the technology may be practiced withoutseveral of the details of the embodiments described below with referenceto FIGS. 2-5 .

FIG. 2 is a partially schematic cross-sectional view of an SST assembly200 configured in accordance with embodiments of the present technology.The SST assembly 200 includes a support substrate 202, one or more SSTdevices 204 (identified individually as a first SST device 204 a and asecond SST device 204 b), and a converter material 206 spaced apart fromthe SST devices 204 on a forward-facing surface 210 of the supportsubstrate 202. The SST assembly 200 has a front side 208 a from whichemissions from the SST devices 204 and the converter material 206 exitthe SST assembly 200 and a back side 208 b generally opposite the frontside 208 a. In the embodiment illustrated in FIG. 2 , for example, theSST devices 204 face backward toward the back side 208 b of the SSTassembly 200 such that the SST emissions initially project generallybackward toward the back side 208 b of the SST assembly 200 (i.e.,generally away from the front side 208 a). As indicated by the arrows,at least a portion of the initial SST emissions strike the surface ofthe converter material 206 and reflect toward the front side 208 a wherethey can exit the SST assembly 200 via an opening 214. Accordingly, atleast a portion of the emissions from the SST devices 204 can reflectoff of the surface of the converter material 206 back toward the frontside 208 a of the SST assembly 200, while other portions of the SSTemissions can travel partially and/or fully through the thickness of theconverter material 206 to the front-facing surface 210 of the supportsubstrate 202 before being redirected toward the front side 208 a of theSST assembly 200. Accordingly, the portion of the SST emissions thatreflect directly from the converter material 206 and exit through theopening 214 avoid multiple reflections and other attenuation caused byfirst passing through the converter material 206. The SST assembly 200can accordingly have light extraction efficiency.

In the embodiment illustrated in FIG. 2 , the support substrate 202includes a flanged portion 212 or shoulder having a support surface 216generally facing the back side 208 b of the SST assembly 200 on whichthe SST devices 204 can be mounted. As such, the SST emissions initiallytravel from the SST devices 204 toward the back side 208 b of the SSTassembly 200 where they strike the remote converter material 206 and/orthe underlying forward-facing surface 210 before being reflected towardthe front side 208 a. For clarity, two SST devices 204 are shown mountedon the flanged portion 212 of the support substrate 202. However, theflanged portion 212 can extend around an inner circumference of thesupport substrate 202 (e.g., having a rectilinear, circular, annular,irregular, and/or other suitable shape), and can support one or morethan two SST devices 204.

The forward-facing surface 210 and/or the overlying converter material206 can be shaped to redirect the emissions generally forward toward theopening 214 in a manner that inhibits multiple reflections of the SSTemissions off of other surfaces within of the SST assembly 200 and toenhance light extraction from the SST assembly 200. For example, asshown in FIG. 2 , the forward-facing surface 210 can have asemi-circular cross-sectional shape that is curved toward the front side208 a of the SST assembly 200 (i.e., concave relative to the front side208 a). In other embodiments, the forward-facing surface 210 can beangled and/or otherwise shaped to direct emissions toward the opening214.

The support substrate 202 can be made from various suitable materialsfor supporting one or more SST devices 204. For example, the supportsubstrate 202 can be made from metals and/or metal alloys (e.g., copper,aluminum, aluminum nitride, etc.) that have a high thermal conductivityto function as a heat sink and thereby decrease the operatingtemperature of the SST assembly 200. In other embodiments, the supportsubstrate 202 can be made from silicon, sapphire, and/or other suitablenonconductive or conductive materials.

In certain embodiments, the forward-facing surface 210 can be a highlyreflective material 218 (shown in broken lines) to efficiently reflectthe emissions toward the front side 208 a of the SST assembly 200. Thereflective material 218 can be formed on the support substrate 202 usingchemical vapor deposition (“CVD”), physical vapor deposition (“PVD”),atomic layer deposition (“ALD”), plating, and/or other suitableformation techniques known in the arts. In other embodiments, thereflective material 218 can also be formed on other surfaces of the SSTassembly 200 (e.g., the support surface 216), or the support substrate202 itself can be formed from the reflective material 218. Thereflective material 218 can include gold (Au), copper (Cu), silver (Ag),aluminum (Al), alloys thereof, and/or any other suitable material thatreflects emissions from the SST devices 204 and/or the convertermaterial 206. In various embodiments, the reflective material 218 can beselected based on its thermal conductivity and/or the color of light itreflects. For example, silver generally does not alter the color of thereflected light. Gold, copper, or other colored reflective materials canaffect the color of the light, and can accordingly be selected toproduce a desired color for the light emitted by the SST assembly 200.

Whether reflective or not, the forward-facing surface 210 can carry theconverter material 206 such that the emissions (e.g., light) directedtoward the back side 208 b of the SST assembly 200 irradiate energizedparticles (e.g., electrons and/or photons) of the converter material206. The irradiated converter material 206 can emit a light of a certainquality (e.g., color, warmth, intensity, etc.). For example, theirradiated converter material 206 can emit light having a differentcolor (e.g., yellow light) than the light emitted by the SST devices 204(e.g., blue light). The light emitted by the converter material 206 cancombine with the light emitted by the SST devices 204 to produce adesired color of light (e.g., white light).

The converter material 206 can include a phosphor containing a dopedyttrium aluminum garnet (YAG) (e.g., cerium (III)) at a particularconcentration for emitting a range of colors (e.g., yellow to red) underphotoluminescence. In other embodiments, the converter material 206 caninclude neodymium-doped YAG, neodymium-chromium double-doped YAG,erbium-doped YAG, ytterbium-doped YAG, neodymium-cerium double-dopedYAG, holmium-chromium-thulium triple-doped YAG, thulium-doped YAG,chromium (IV)-doped YAG, dysprosium-doped YAG, samarium-doped YAG,terbium-doped YAG, and/or other suitable wavelength conversionmaterials. In further embodiments, the converter material 206 caninclude silicate phosphor, nitrate phosphor, aluminate phosphor and/orother types of salt or ester based phosphors.

In the embodiment illustrated in FIG. 2 , the converter material 206 atleast generally conforms to the forward-facing surface 210 and has an atleast generally uniform thickness, and therefore has a generallysemi-circular shape in FIG. 2 . The conformal converter material 206 canhave a thickness such that more emissions reflect from the surface ofthe converter material 206 than pass through it. In other embodiments,the converter material 206 can have other suitable cross-sectionalshapes and configurations with respect to the underlying forward-facingsurface 210 and/or other surfaces of the SST assembly 200. For example,the shape of the forward-facing surface 210 and the converter material206 can be optimized with respect to the positioning of the SST devices204 to avoid SST emissions (e.g., blue light) from exiting the SSTassembly 200 before striking the converter material 206. In otherembodiments, the converter material 206 can have a non-uniform thicknessat selected areas of the forward-facing surface 210 to control the colorof light at selected areas of the opening 214. The converter material206 can be formed on the forward-facing surface 210 using CVP, PVD, ALD,and/or other suitable deposition methods known in the art.

As discussed above, the remotely-positioned converter material 206 isnot in direct contact with the SST devices 204, nor do all of theemissions from the SST devices 204 penetrate into or otherwise passcompletely through the converter material 206. The converter material206 therefore experiences less heating from the SST devices 204, whichallows for the use of alternative converter materials that may besensitive to the operating temperatures induced by conventional SSTdevices. For example, the SST assembly 200 can include organic convertermaterials, high refractive index silicone, and/or other suitableconverter materials that may have heat-sensitive properties. The lowertemperatures in the converter material 206 may also increase theoperating life of the converter material 206, enhance the efficiency ofthe converter material 206, and/or may enhance the control over thecolor of light (i.e., the mixture of wavelengths) emitted by the SSTassembly 200.

The individual SST devices 204 can include an SST structure 220 carriedby a substrate 222. The substrate 222 can be comprised of generallysimilar materials as the support substrate 202 (e.g., polymers, silicon,metals, metal allows, etc.) and/or other suitable substrate materials.The SST structure 220 can be formed using metal organic chemical vapordeposition (“MOCVD”), molecular beam epitaxy (“MBE”), liquid phaseepitaxy (“LPE”), and/or hydride vapor phase epitaxy (“HVPE”), and/orother suitable epitaxial growth techniques known in the arts. In certainembodiments, the SST structure 220 can be formed on a growth substrateand subsequently attached to the substrate 222. In other embodiments,the SST structure 220 can be formed directly on the substrate 222, andtherefore the substrate 222 can be made from sapphire and/or othersuitable materials for growth substrates. In further embodiments, thesubstrate 222 can be omitted, and the SST structure 220 can be mounteddirectly on support substrate 202 (e.g., using a chip-on-boardapproach).

The SST structure 220 can include an active region between twosemiconductor materials. For example, a first semiconductor material caninclude a P-type semiconductor material (e.g., a P-type gallium nitride(″P-GaN″)), and a second semiconductor material can include an N-typesemiconductor (e.g., an N-type gallium nitride (″N-GaN″)). In selectedembodiments, the first and second semiconductor materials canindividually include at least one of gallium arsenide (GaAs), aluminumgallium arsenide (AlGaAs), gallium arsenide phosphide (GaAsP), gallium(III) phosphide (GaP), zinc selenide (ZnSe), boron nitride (BN),aluminum gallium nitride (AlGaN), and/or other suitable semiconductormaterials. The active region can include a single quantum well (″SQW”),MQWs, and/or a bulk semiconductor material. The term ″bulk semiconductormaterial″ generally refers to a single grain semiconductor material(e.g., InGaN) with a thickness between approximately 10 nanometers andapproximately 500 nanometers. In certain embodiments, the active regioncan include an InGaN SQW, GaN/InGaN MQWs, and/or an InGaN bulk material.In other embodiments, the active region can include aluminum galliumindium phosphide (AlGaInP), aluminum gallium indium nitride (AlGaInN),and/or other suitable materials or configurations. In certainembodiments, the SST structure 220 can be configured to emit light inthe visible spectrum (e.g., from about 390 nm to about 750 nm), in theinfrared spectrum (e.g., from about 1050 nm to about 1550 nm), and/or inother suitable spectra.

As further shown in FIG. 2 , the individual SST devices 204 canoptionally include a cover feature 224, such as a lens or encapsulantthat transmits emissions generated by the SST structure 220. The coverfeatures 224 can be made from a transmissive material includingsilicone, polymethylmethacrylate (PMMA), resin, or other suitabletransmissive materials. In the embodiment illustrated in FIG. 2 , thecover features 224 have a generally hemispherical shape. In otherembodiments, the cover features 224 can have different shapes tocollimate, scatter, and/or otherwise modulate light or other emissionsfrom the SST structure 220. For example, in several embodiments, thecover features 224 can be configured to direct emissions from theunderlying SST structure 220 toward the forward-facing surface 210 or aspecific portion thereof to encourage reflection toward the opening 214at the front side 208 a of the SST assembly 200.

Several embodiments of the SST assembly 200 shown in FIG. 2 can haveenhanced light extraction efficiencies. As explained above withreference to FIGS. 1A-1C, conventional SST devices may be inefficientbecause, among other reasons, the emissions from the SST structure musttravel completely through a converter material (e.g., phosphor) beforeexiting the device, which dissipates the emissions. Additionally, therandomized dispersion of photons from the converter material can resultin multiple reflections of the emissions from various surfaces of theSST device, resulting in further dissipation of the emissions and adecrease in the extraction efficiency. For example, the emissions of aconventional SST device with a remotely-positioned converter materialmay incur on average 7 or more reflections before exiting the SSTdevice. Even assuming that the SST device includes highly reflectivesurfaces (e.g., 97% reflectivity with only 3% of the emissions lost uponeach reflection), the multiple reflections still result in substantialemission losses (e.g., 19%). In a conventional SST device having aluminous efficacy of radiation of 330 Im/W and an average photon energyof the final spectrum of about 82% (e.g., as in some conventionalremote-converter material SST devices), the SST device would deliverapproximately 220 Im/W luminous efficacy from the SST structure.

The SST assembly 200 shown in FIG. 2 avoids the problems of conventionalSST devices by spacing or otherwise locating the converter material 206apart from the SST structure 220 such that at least a portion of theemissions of the SST assembly 200 do not pass completely through thethickness of the converter material 206 before being extracted from theSST assembly 200. Instead, the surface of the converter material 206reflects incident SST emissions and, in certain embodiments, may reflectmore SST emissions than the other surfaces of the SST assembly 200(e.g., the forward-facing surface 210). Intermediate portions of theconverter material 206 may also direct some of the SST emissions towardthe opening 214 before the SST emissions pass completely through thefull thickness of the converter material 206. The SST emissionsreflected off of the converter material 206 do not dissipate as theywould if they were to travel completely through the full thickness “t”of the converter material 206, and are therefore not subject to therandomized dispersion of emissions that results in multiple reflections.The fraction of the SST emissions that passes completely through thefull thickness “t” of the converter material 206 is reflected by theunderlying forward-facing surface 210. The shape of the forward-facingsurface 210, along with the reflective material 218 on theforward-facing surface 210, can direct the emissions toward the frontside 208 a of the SST assembly 200 where they can be extracted throughthe opening 214. These emissions from the SST assembly 200 are thereforeless prone to multiple reflections that dissipate the extractionefficiency. Even assuming that the SST emissions would incur an averageof two reflection events, the SST assembly 200 (e.g., having a luminousefficacy of radiation of 330 Im/W) would still deliver about 255 Im/Wluminous efficacy, which is an improvement of 16% over conventionalremote-converter material devices.

FIG. 3 is a partially schematic cross-sectional view of an SST assembly300 configured in accordance with other embodiments of the presenttechnology. The SST assembly 300 can include features generally similarto the features of the SST assembly 200 described with reference to FIG.2 . For example, the SST assembly 300 can include an SST device 304carried by a support surface 316 of a support substrate 302,forward-facing surfaces 310 made from and/or coated with a reflectivematerial 318, and a converter material 306 on the forward-facingsurfaces 310.

In the embodiment illustrated in FIG. 3 , the forward-facing surfaces310 extend at an angle from the support surface 316 toward a front side308 a of the SST assembly 300. Rather than facing a back side 308 b ofthe SST assembly 300, the SST device 304 shown in FIG. 3 faces generallytoward an opening 314 of the support substrate 302 at the front side 308a of the SST assembly 300. However, the SST emissions do not radiatedirectly forward through the opening 314. Instead, as shown in FIG. 3 ,a cover feature 324 can be positioned over the SST structure 220 andconfigured to direct the SST emissions generally toward the convertermaterial 306 on the forward-facing surfaces 310 of the support substrate302 such that at least a portion of the SST emissions strike theconverter material 306 before exiting the SST assembly 300. In theillustrated embodiment, for example, the cover feature 324 includes atleast two lobes 326 that concentrate and direct the SST emissionsradially outward toward the forward-facing surfaces 310. At least aportion of the emissions can reflect off of the angled convertermaterial 306 and exit the SST assembly 300 without incurring multiplereflections or dissipating as they travel into the converter material306. As discussed above, the remotely-positioned converter material 306can be comprised of a broad range of materials, such as heat-sensitiveconverter materials, because the converter material 306 is not directlyheated by the SST device 304. A portion of the SST emissions that passesthrough the complete thickness of the converter material 306 can reflectoff of the underlying reflective material 318. Because theforward-facing surfaces 310 are spaced apart from the SST device 304,they are not constrained by the operating parameters of the SST device304 and can therefore be optimized for reflectivity. In otherembodiments, the converter material 306 and/or the underlying supportsubstrate 302 can have other suitable shapes and configurations forextracting emissions from the SST assembly 300 without the emissionscompletely passing through the converter material 306, and the coverfeature 324 can be designed for the specific configuration of theconverter material 306.

FIG. 4 , for example, is a partially schematic cross-sectional view ofan SST assembly 400 configured in accordance with further embodiments ofthe present technology. The SST assembly 400 includes features generallysimilar to the features of the SST assembly 300 described with referenceto FIG. 3 . However, the SST assembly 400 includes a plurality of SSTdevices 404 positioned next to one another on a support surface 416 of asupport substrate 402. Each SST device 404 includes a cover feature 424that directs the SST emissions of the individual SST devices 404 towarda forward-facing surface 410 positioned proximate to the individual SSTdevices 404. In certain embodiments, the SST devices 404 can be arrangedin a rectilinear array on the support surface 416, and theforward-facing sidewalls 410 can extend from the support surface 416 ina similar rectilinear pattern. The cover features 424 can be configuredto direct SST emissions toward the closest sidewall 410. In otherembodiments, the forward-facing surfaces 410 can extend from the supportsurface 416 to form a blunt cone shape or a hemispherical shape, and theSST devices 404 can be configured in a circular array with the coverfeatures 424 directing the SST emissions radially outward. In furtherembodiments, the forward-facing surfaces 410, the converter material406, and/or the support substrate 402 can have other suitableconfigurations that allow emissions from the SST devices 404 to strikethe converter material 406 without penetrating completely through itbefore exiting the SST assembly 400.

Any one of the SST assemblies described above with reference to FIGS.2-4 can be incorporated into any of a myriad of larger and/or morecomplex systems, a representative example of which is system 500 shownschematically in FIG. 5 . The system 500 can include an SST assembly510, a power source 520, a driver 530, a processor 540, and/or othersubsystems or components 550. The resulting system 500 can perform anyof a wide variety of functions, such as backlighting, generalillumination, power generations, sensors, and/or other suitablefunctions. Accordingly, representative systems 500 can include, withoutlimitation, hand-held devices (e.g., mobile phones, tablets, digitalreaders, and digital audio players), lasers, photovoltaic cells, remotecontrols, computers, and appliances. Components of the system 500 may behoused in a single unit or distributed over multiple, interconnectedunits (e.g., through a communications network). The components of thesystem 500 can also include local and/or remote memory storage devices,and any of a wide variety of computer readable media.

From the foregoing, it will be appreciated that specific embodiments ofthe technology have been described herein for purposes of illustration,but that various modifications may be made without deviating from thedisclosure. For example, in FIGS. 2-4 , the SST devices individuallyinclude an SST structure mounted on a carrier substrate, which is inturn mounted on the underlying support surface of the support substrate.However, in other embodiments, the SST structures can be mounteddirectly on the support substrate of the SST assemblies using achip-on-board approach and/or other suitable formation. Additionally,the illustrated embodiments are only representative examples of thesuitable support substrate configurations for SST assemblies inaccordance with the present technology. Other embodiments of SSTassemblies can include support substrates having other suitable shapesthat allow SST emissions to exit the SST assembly without fully passingthrough a converter material. Certain aspects of the new technologydescribed in the context of particular embodiments may be combined oreliminated in other embodiments. Moreover, although advantagesassociated with certain embodiments of the new technology have beendescribed in the context of those embodiments, other embodiments mayalso exhibit such advantages and not all embodiments need necessarilyexhibit such advantages to fall within the scope of the technology.Accordingly, the disclosure and associated technology can encompassother embodiments not expressly shown or described herein.

I/We claim:
 1. A solid-state transducer (SST) assembly having a frontside from which emissions are configured to exit the SST assembly and aback side opposite the front side, the SST assembly comprising: asupport substrate having a forward-facing surface and an opening fromwhich the emissions are configured exit the SST assembly; an SSTstructure carried by the support substrate and configured to generatethe emissions; and a wavelength converter material spaced apart from theSST structure, wherein the forward-facing surface and the wavelengthconverter material are configured such that at least a portion of theemissions that exit the SST assembly at the front side reflect from anouter surface of the wavelength converter material directly through theopening and do not pass completely through the thickness of thewavelength converter material .
 2. The SST assembly of claim 1 wherein:the support substrate includes a flanged portion at an innercircumference of the support substrate, the flanged portion having asupport surface carrying the SST structure, wherein the support surfaceand the SST structure face generally toward the back side of the SSTstructure; the forward-facing surface extends from the flanged portiontoward the back side of the SST assembly, the forward-facing surfacebeing shaped to direct the emissions through the opening; theforward-facing surface includes a reflective material; the wavelengthconverter material is on the reflective material at the forward-facingsurface; and the SST structure includes a first semiconductor materialcomprising N-type gallium nitride (N-GaN), a second semiconductormaterial comprising a P-type gallium nitride (P-GaN), and an activeregion comprising indium gallium nitride (InGaN), the active regionbeing between the first and second semiconductor materials.
 3. The SSTassembly of claim 1 wherein: the SST structure faces generally towardthe back side of the SST assembly; the forward-facing surface ispositioned toward the back side of the SST assembly relative to the SSTstructure; the wavelength converter material is on the forward-facingsurface; and the SST assembly is configured such that the emissionsinitially travel generally toward the back side of the SST assemblywhere at least the portion of the emissions strike the outer surface ofthe wavelength converter material and reflect toward the front side toexit the SST assembly.
 4. The SST assembly of claim 3 wherein theforward-facing surface has a substantially semicircular cross-sectionalshape.
 5. The SST assembly of claim 1 wherein: the support substrateincludes a support surface that carries the SST structure and facesgenerally toward the front side of the SST assembly; the forward-facingsurface is spaced laterally outward from the support surface and isangled toward the front side; the forward-facing surface comprises areflective material; the converter material is on the reflectivematerial of the forward-facing surface; and the SST assembly furtherincludes a cover feature on the SST structure, the cover feature beingconfigured to direct at least the portion of the emissions generallytoward the forward-facing surface.
 6. The SST assembly of claim 1,further comprising a cover feature on the SST structure, the coverfeature being shaped to direct the emissions generally toward theforward-facing surface.
 7. The SST assembly of claim 6 wherein the coverfeature comprises a first lobe configured to direct a first portion ofthe SST emissions laterally outward in a first direction and a secondlobe configured to direct a second portion of the SST emissionslaterally outward in a second direction different from the firstdirection.
 8. The SST assembly of claim 1 wherein the wavelengthconverter material comprises a phosphorous material.
 9. The SST assemblyof claim 1 wherein the forward-facing surface is reflective, and whereinthe wavelength converter material is conformal to the forward-facingsurface.
 10. The SST assembly of claim 9 wherein the forward-facingsurface and the wavelength converter material are angled and/or curvedtoward the front side of the SST assembly.
 11. A lighting systemcomprising: a solid-state transducer (SST) assembly having a front sideand a back side opposite the front side, the SST assembly comprising: asupport substrate having a forward-facing surface and an opening fromwhich light is configured exit the SST assembly; an SST structurecarried by the support substrate and configured to generate the light;and a wavelength converter material spaced apart from the SST structure,wherein the forward-facing surface and the wavelength converter materialare configured such that at least a portion of the light that exits theSST assembly at the front side reflects from an outer surface of thewavelength converter material directly through the opening and does notpass completely through the thickness of the wavelength convertermaterial; and a driver operably coupled to the SST assembly.
 12. Thelighting system of claim 11 wherein the light emitted by the SSTstructure initially travels generally toward the back side of the SSTassembly before being reflected toward the front side by the convertermaterial and/or the forward-facing surface.
 13. The lighting system ofclaim 11 wherein: the forward-facing surface comprises a reflectivematerial; and the converter material is on at least a portion of thereflective material.
 14. The lighting system of claim 11 wherein: theSST structure faces generally toward the front side of the SST assembly;and the forward-facing surface and the converter material are spacedlaterally outward from the SST structure and is angled and/or curvedtoward the front side.
 15. The lighting system of claim 11 wherein theSST assembly further includes a cover feature on the SST structure, thecover feature being configured to direct at least a portion of the lightemitted by the SST structure generally toward the forward-facingsurface.